Climate change has a negative impact on fish social behavior and abundance

Climate change poses a major threat to coral reef ecosystems worldwide. Here, we present the immediate negative effects of recent cyclones and the 2016 El Niño on the abundance of cleaner wrasse <i>Labroides dimidiatus</i> (hereafter ‘cleaner’), a key species for fish biodiversity on coral reefs. We report that 80% of cleaner densities was lost. Consequently, several repercussions on cleaners social behavior were observed. We outline significant decline in the ability of cleaner to manage their own reputation and strategically prioritize certain category of client reef fish, previously documented as key components of cleaner high cognitive performance in the cleaning mutualism. Thus, contemporary climate change may cause diverse and unexpected effects on species abundance and social interactions, possibly due to the loss of more complex cognition.

气候变化对全球珊瑚礁生态系统构成重大威胁。本研究呈现了近期气旋与2016年厄尔尼诺事件对裂唇鱼（*Labroides dimidiatus*，后文简称“清洁鱼”）种群丰度的即时负面影响，该物种是维持珊瑚礁鱼类生物多样性的关键类群。研究观测到清洁鱼的种群密度下降了80%，进而其社会行为出现多方面连锁反应。我们发现，清洁鱼管控自身声誉、以及基于策略优先选择特定客户礁鱼的能力显著下降——此前研究表明，这类能力是清洁鱼在清洁共生关系中展现高认知表现的核心要素。由此可见，当代气候变化可能对物种种群丰度与社会互动产生多样且始料未及的影响，这一效应或源于物种复杂认知能力的丧失。